This invention relates to connectors for making low resistance electrical connections to batteries, namely connectors for making electrical connections to lead-acid automotive batteries.
The prior art includes connectors of the types shown in FIGS. 1 and 2. These connectors present two problems, the first being that only a minimum of the circumferential surface of the battery post is contacted by the connector as the connection bolt is tightened. This results from the deformation of the circular opening defined by the connector as the bolt is tightened. This deformation is inherent in this method of connector tightening.
The second problem, and one that contributes to automotive starting problems, is the corrosion of the connector. This increases the electrical resistance between the connector and the battery post and thus limiting the electrical current flow from the battery during high current usage functions such as starting of the engine. Corrosion also limits the ability of the automotive generator or alternator to recharge the battery. Corrosion results from the use of dissimilar metals which are used in connectors of this type--the lead alloy body and the steel tightening bolt. Whenever, dissimilar metals come into contact there is a natural electro-molecular action between them. Then, when acid fumes are added, this process is accelerated resulting in visible corrosion.
The connector of the present invention provides a connector of a single material which maximizes the surface area of the battery post with which a low resistance electrical contact is made. This connector is a two piece connector with each piece manufactured from the same alloy. The connector includes a body portion for attachment to a cable. It includes a bifurcated portion which defines a pair of spaced-apart ring portions. Each ring-portion defines a circular opening therethrough with its center offset from the center of the respective ring portion. Each of these circular openings are aligned, one with the other and are sized to fit around the tapered battery post.
The second piece of the connector is a locking ring which includes a tab extending outward from the ring with a pair of lugs, one each extending upward and downwad from the planes defined by each side of the ring. The thickness of the ring is sized to permit the insertion of the ring between the two ring portions of the body with the circular opening through the locking ring being substantially the same diameter as the diameters of the circular openings in the body ring portions.
To make the connection to a battery post, the locking ring is inserted into the body in the unlocked position with all three of circular openings aligned. The connector is then slipped onto the battery post. To tighten the connector, the locking ring is turned in either direction causing a constriction of the circular opening of the assembled connector by cam action as the lugs ride on the edge of the body ring portions forcing the circular opening in the locking ring portion out of alignment with the other circular openings. This is caused by the variable wall thickness of the circular openings in the body ring portions which are the result of the offsetting of the center of those circular openings from the center of the body ring portions.